West Brom secured their first win in six Premier League matches courtesy of Gardner's 72nd-minute strike against a visiting side who were reduced to 10 men midway through the first half.
Kieran Richardson's dismissal helped swing the contest in the hosts' favour at The Hawthorns and it was former Villa Park trainee Gardner who forced the crucial breakthrough with a close-range finish.
Gardner ran to celebrate with head coach Irvine, the pair slapping hands, and the Scot sung the 28-year-old's praises at his post-match media conference.
Irvine said: "I wouldn't have minded who Craig had gone to celebrate with, it didn't need to be me. My hand still hurts from what he did.
"He's been a great pro since the first day he came and he's been a great example for all of the players. He's been desperate to score, absolutely desperate, so it'll mean so much to him to have got that goal.
"He practices his shooting every day, he practices his free-kicks day after day. He's just a model pro."
Although West Brom had a man advantage for more than an hour, Irvine still felt his side were up against it, but he praised his players' patience.
"I think everybody assumes it's going to be easy against 10 men," he added. "I didn't take it as a foregone conclusion that we would score.
"I just I felt as long as we kept on making the right decisions, kept our patience and played with intelligence that our chances would come."
The result saw West Brom climb to 14th, three points above the relegation zone.
